(1. 四川大學(xué) 高分子研究所，成都 610065； 2. 四川大學(xué) 化學(xué)工程學(xué)院，成都 610065； 3. 伍倫貢大學(xué) 超導(dǎo)與電子材料研究所，伍倫貢 2522； 4. 成都理工大學(xué) 材料與化學(xué)化工學(xué)院，成都 610059)
摘 要: 采用原位誘導(dǎo)法制備得到了一系列xLiM2O4？(1-x)LiNi1/3Co1/3Mn1/3O2(M=Ni, Co, Mn; x=0, 0.1, 0.2, 0.3, 0.4, 0.5)尖晶石/層狀異質(zhì)結(jié)構(gòu)復(fù)合材料。借助X射線衍射、掃描電鏡、差示掃描量熱儀、恒電流間歇滴定技術(shù)和恒電流充放電測試表征手段對材料的晶體結(jié)構(gòu)、微觀形貌和電化學(xué)性能進(jìn)行了研究。電化學(xué)性能結(jié)果表明：x=0.2材料的倍率性能和循環(huán)性能最佳，在2.7~4.3 V、1C下循環(huán)100次后，放電比容量為137 mA？h/g，容量保持率為93%；10C時(shí)的放電比容量為112 mA？h/g，相比于原始LiNi1/3Co1/3Mn1/3O2材料在10C的放電比容量(95 mA？h/g)有較大提高。此外，快充慢放能力測試也證實(shí)了該材料的結(jié)構(gòu)穩(wěn)定，其在5C充、1C放的充放電機(jī)制下，循環(huán)100次后的放電比容量還能高達(dá)120 mA？h/g，容量保持率為87%。恒電流間歇滴定技術(shù)(GITT)的結(jié)果表明。x=0.2材料的DLi+值比原始LiNi1/3Co1/3Mn1/3O2材料的要高出一個(gè)數(shù)量級，說明尖晶石相的引入從根本上改善了材料的電化學(xué)性能。
關(guān)鍵字: 異質(zhì)尖晶石/層狀結(jié)構(gòu)；LiNi1/3Co1/3Mn1/3O2；鋰離子電池；電化學(xué)性能
（1. Polymer Research Institute, Sichuan University, Chengdu 610065, China; 2. School of Chemical Engineering, Sichuan University, Chengdu 610065, China; 3. Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong NSW 2522, Australia; 4. College of Materials and Chemistry and Chemical Engineering, Chengdu University of Technology, Chengdu 610059, China）
Abstract:A series of heterostructured spinel/layered xLiM2O4？(1-x)LiNi1/3Co1/3Mn1/3O2 (M=Ni, Co, Mn; x=0, 0.1, 0.2, 0.3, 0.4, 0.5) cathodes were prepared by in-situ induced coating method. Powder X-ray diffractometry (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), galvanostetic intermittent titration technique (GITT) and galvanostatic charge-discharge tests were employed to analyze the crystal structure, micromorphology and electrochemical properties of the as prepared materials. Electrochemical results indicate that the x=0.2 sample has the best rate performance and long-term cycling stability. It delivers a discharge capacity of 137 mA？h/g at 2.7-4.3 V and 1C after 100 cycles, with the outstanding capacity retention being 93%. At 10C, the specific capacity of the material is 112 mA？h/g, which is improved greatly when compared with the pristine LiNi1/3Co1/3Mn1/3O2 (95 mA？h/g at 10C). Additionally, the fast-charging test results are indicative of the fact that this cathode has sufficiently stable structure, because it can still deliver a discharge capacity higher than 120 mA？h/g after 100 cycles with capacity retention of 87% at 5C charge and 1C discharge. Galvanostatic intermittent titration technique (GITT) results show that DLi+ of x=0.2 sample is higher by one order of magnitude than the pristine LiNi1/3Co1/3Mn1/3O2, indicating that the introduced spinel phase could fundamentally enhance the electrochemical performance for cathodes.
Key words: heterostructured spinel/layered; LiNi1/3Co1/3Mn1/3O2; lithium-ion battery; electrochemical performance
